The present invention relates to a skin test device that is used for patch testing and other variables to determine an allergen (antigen) which is associated with contact dermatitis, asthma or food allergy and which triggers eczema, dermatitis or drug eruption.
In the modern world where many different chemicals are commonly and widely used, diseases caused by uptake of or contact with chemicals become more and more common. For example, it is well known that allergic symptoms such as eczema may occur as a result of skin contact with chemicals in cosmetic preparations or accessories such as necklaces or pierces. Such a skin reaction is called “contact dermatitis”.
A prevention against the contact dermatitis as well as asthma and food allergies is to identify the causative substance, i.e., allergen, and avoid exposure to it. Patch testing is widely used for this purpose. In patch testing, a suspected allergen is prepared in a solvent such as water or vaseline. The sample is placed on the skin and kept for a given period of time. Hives or blisters indicates a positive response. The substance contained in the sample is identified as the subject's allergen.
Patch testing may require application of a sample in an adequate concentration to the skin. Direct application of the sample to the skin of a subject has, however, many problems in conjunction with formulation and operations of application. With this respect, more convenient and easier approaches have been used to place samples on the skin. Ready-to-use skin test devices are typical examples in which suspected allergen is provided already applied to a fabric or a plastic panel. Some ready-to-use skin test devices comprise two or more samples of suspected allergens that are consistently placed thereon in order to test for the allergens together.
As apparent from the above, skin test devices significantly decrease troubles associated with patch testing. However, these skin test devices are not perfect.
A major problem of the conventional skin test devices is impossibility to observe the skin condition during their staying on the skin. A patch test may be continued even under the condition that a causative allergen can be identified from hives or blisters. This problem is more noticeable for a ready-to-use device that contains several samples because skin normally responds to different suspected allergens in various degrees. When a patch test is continued until allergic reactions develop fully for all allergens, undesirable reactions such as blisters can occur as a result of excessive exposure to allergens highly prone to cause the allergic reactions. Higher levels than is necessary for the identification tend to cause blisters on the skin, which may cause after-effects such as pigmentation. This is not desirable on the aesthetic and health considerations of the subject.
In a sense, such situations stem from a longer response time (e.g., 48 hours) that is required for certain allergens to cause hives or blisters on the skin of a subject. Taking this issue into consideration, some approaches place samples in the skin via small scratches or pricks in order to develop reactions to the allergens for a shorter period of time. The time required for reaction is reduced by means of delivering the samples into the body. Pricking the skin before application of the samples is rather troublesome. It is cumbersome to consistently prick the skin at the exact locations where samples should be placed especially when these samples are ready-to-use on a single skin test device.
A broad object of the present invention is to solve the problems associated with conventional skin test devices and make this kind of skin testing widely popularized.
More specifically, it is an object of the present invention to provide a skin test device that does not cause excessive skin reactions during testing.
It is another object of the present invention to provide a skin test device with which skin testing can be done for a shorter period of time without reducing the precision of the test.